Hexokinase vs Glucokinase

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Glucokinase and Hexokinase are enzymes which phosphorylate glucose to glucose-6-phosphate, trapping glucose inside the cell.

Glucokinase is present in hepatocytes of the liver and beta cells of pancreas, tissues that needs to quickly respond to changes in glucose levels. Compared to hexokinase, glucokinase has a higher Km (lower binding affinity) and a higher Vmax (increased capacity). Glucokinase is induced by insulin, and defects in glucokinase can caused maturity-onset diabetes of the young (MODY).

Hexokinase is found in most tissues. Compared to glucokinase, hexokinase has a lower Km (higher binding affinity) and lower Vmax (lower capacity). Notably, the enzyme is not induced by insulin, but does undergo negative feedback inhibition by glucose-6-phosphate.

Find Hexokinase and Glucokinase and more Metabolism topics among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Shelf Exams.